Route guidance system and route guidance method

Abstract

A route guidance system includes a current position detection section, a route search section, and a guidance section. The guidance section includes a branch computation section computes the number of branches between a host vehicle location and a guidance location along a specified route. A point guidance section executes route guidance based on the computed number of the branches. The number of branches between the host vehicle location and the guidance location is computed, and the route guidance is executed based on the computed number of the branches, so it is possible to recognize the guidance location simply by counting the number of the branches, regardless of the number of traffic signals that exist between the host vehicle location and the guidance location.

1. A route guidance system, comprising:
 a current location detection section that detects a current location of a host vehicle as a host vehicle location; 
 route search processing means for searching for a route to a destination, based on the detected host vehicle location and for specifying the route determined by a search as a specified route; and 
 guidance processing means for settling a route guidance point at a specified location on the specified route in advance of a guidance location for which route guidance is to be provided and that executes route guidance for the guidance location when the vehicle arrives at the route guidance point, wherein 
 the guidance processing means includes: 
 branch number computation means for computing the number of branches in the specified route between the host vehicle and the guidance location; 
 point guidance processing means for outputting route guidance by voice to a driver of the host vehicle, based on the computed number of the branches, during an announcement time period extending from the start to the end of the outputting of the route guidance by voice, when the host vehicle comes to the set route guidance point; 
 vehicle speed detection means for detecting speed of the host vehicle; 
 guidance suspension conditions determination processing means for determining whether or not guidance suspension conditions are applicable, based on an announcement period travel distance that is computed based on the announcement time period and the vehicle speed, wherein the guidance suspension conditions are determined to be applicable when the route guidance point is within the announcement time period travel distance; and 
 guidance suspension processing means for, responsive to a determination that the guidance suspension conditions are applicable, suspending the route guidance which is based on the computed number of branches. 
 
     
     
       2. The route guidance system according to  claim 1 , wherein the branches are intersections. 
     
     
       3. The route guidance system according to  claim 1 , wherein the branches are junctions with roads. 
     
     
       4. The route guidance system according to  claim 3 , wherein the roads are roads that extended in the same direction as an exit road from the guidance location. 
     
     
       5. The route guidance system according to  claim 1 , wherein
 the guidance processing means includes a traffic signal determination processing means that determines whether or not a traffic signal exists at the guidance location; and 
 if a traffic signal is determined to exist at the guidance location, the point guidance processing means includes the existence of the traffic signal in the route guidance that is based on the number of the branches. 
 
     
     
       6. The route guidance system according to  claim 1 , wherein
 the guidance processing means includes a specific branch determination processing means for determining whether or not a specific type of branch is present between the host vehicle location and the guidance location that the driver might possibly count by mistake; and 
 the guidance processing means includes a delay processing means for, responsive to a determination that a branch of the specific type is present, delaying the route guidance, then executing the route guidance after the vehicle has passed the branch of the specific type. 
 
     
     
       7. A route guidance method, comprising the steps of:
 detecting a current location of a host vehicle as a host vehicle location; 
 detecting speed of the host vehicle; 
 searching for a route to a destination, based on the host vehicle location and search data read from data storage, setting a route determined by the searching as a specified route, and outputting route data that describes the specified route; 
 based on the output route data, identifying a guidance location for which route guidance is to be provided; 
 setting a route guidance point at a specified location on the specified route in advance of the guidance location for which route guidance is to be provided; 
 computing the number of branches in the specified route, between the host vehicle location and the guidance location; 
 outputting route guidance for the guidance location by voice to a driver of the host vehicle during an announcement time period when the vehicle arrives at the route guidance point, based on the computed number of branches, when the host vehicle comes to the set route guidance point, the announcement time period extending from the start to the end of the outputting of the route guidance by voice; 
 determining whether or not guidance suspension conditions are applicable, based on an announcement time period travel distance that is computed based on the announcement time period and the vehicle speed, wherein the guidance suspension conditions are determined to be applicable when the route guidance point is within the announcement time period travel distance; and 
 suspending the route guidance based on the computed number of branches responsive to a determination that the guidance suspension conditions are applicable.